<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		<div>1</div>
		<div>2</div>
		<div>3</div>
		<div>4</div>
	</body>
	<script type="text/javascript">
		var arr ={};
		arr.length=3;
		arr[0]=0;
		arr[1]=1;
		arr[2]=2;
		
		
		var arr2 = Array.prototype.slice.call( arr );
		arr2.push(3)
		console.log(arr2);
	</script>
</html>
